Bulimia nervosa.

Bulimia nervosa (BN) is common and has a global presence and burden. BN shares features with anorexia nervosa and binge eating disorder, but its cardinal feature is recurrent binge eating followed by extreme weight control or compensatory behaviours in association with high levels of weight and shape, and other body image and eating, preoccupations. The last three decades have seen advances in understanding the risk factors and psychobehavioural mechanisms of BN. These advances have informed primary prevention programmes that are effective in preventing the onset of risk factors and, in one selective programme, the onset of BN itself. First-line treatment for BN is psychological therapy, namely cognitive behaviour therapy for eating disorders. However, the challenge of a large treatment gap and the need to improve prevention and early detection of BN remains. Adaptations of treatments to increase their accessibility and reduce cost, alongside the growth of co-design and incorporation of lived experience expertise in research, are assisting in developing programmes that may effectively close this treatment gap. An increasingly sophisticated approach to understanding the neuroscience of BN has the potential to inform novel treatments in both psychological and biological spheres.